Circuit controlling device



May 16, 1939. c. w. KUHN CIRCUIT CONTROLLING DEVICE Z Sheets-Sheet 1Filed NOV. 23, 1936 4 00 0 u 5 O W MK H 0 Q 4 5 O L c 7. v A 5 air a n40/ m 5 5,5 mm w" v I 1A1 w b /k WXM May 16, 1939. c. w. KUHN CIRCUITCONTROLLING DEVICE Filed Nov. 23, 1936 2 Sheets-Sheet 2 awn... 1c, 1939UNI ED STATES PATENT OFFICE Cutler-Hammer, Ina, poration 02 Delaware swn.-

Applicaflon Nave-b8 23. 1; Serial No. 112,231

9 Claims. (Cl. III-83) This invention relates to circuit controllingdevices,.and while not limited thereto is particularly applicabletodevices for. controlling electric refrigerators of the domestic type.

The invention has among its obiects to provide an improved automaticcircuit controlling device for electric refrigerators which isadjustable at will to vary the temperature maintained within therefrigerator or to render the refrigerator inoperativefor defrosting.

Another object is to provide a rugged and canpact control device of theaforesaid character which consists of a relatively small number of partswhich can be readily manufactured and assembled.

Another object is to provide a control device of the aforesaid characterhaving an improved snap switch mechanism therewith which is simple inconstruction and exceedingly go positive and reliable in operation.

Various other objects and advantages of the invention will hereinafterappear.

The accompanying drawings illustrate an embodiment of the inventionwhich -will now be described, it being understood'that the embodimentillustrated is susceptible of modification without departing from thespirit and scope of the appended claims.

In the drawings: 7

Figure 1 is a side eievational view of a control device embodying theinvention, a cover and a front plate for the devigebeing shown insection;

Fig. 2 is a fr evational view of the device showninl'igf 1, the coverand front plate being mmbved;

Figs. 3 and 4 are vertical side sectional views of the control deviceshown in Fig. 1 illustrating the device in circuit opening and circuitclosing position;

Figs. 5 and 6 are sectional views on lines I-I and I-.-I, respectively,of Fig. 1;

Fig. '7 is a sectional view on line 1-1 of Fig. 2,

' and Figs. 8, 9 and 10 are perspective views of certain parts of thecontrol device.

The control device illustrated in the drawings includes an elongatedinsulating base I which carries a control switch includinga pair ofstationary contacts 2 and I and a cooperating bridging contact I.Stationary contacts 2 and I are mounted within openings adjacent thelower end of insulating base I, and bridging contact s is mounted upon apivoted contact carrier I having aspringIassociatedtherewithforbiasingtbe same in adirection to hold said bridg g contact inengagement withsaid stationary contact.

Contact carrier I is controlled by a fluid condition responsive device Ithrough the medium of a snap operating mechanism including pivoted 5levers I and 9 and an over-center spring Ill. Said fluid conditionresponsive device has a loading spring ll associated therewith which isadiustable by a screw l2 having an operating knob II ilxed thereto. Asshown in Fig. 5, knob I3 is provided with a cam projection II and ashereinother set forth upon movement oi said knob into a given extremeposition lever 9 is operated by said cam projection to move bridgingcontact I into open position. v

More specifically, contact carrier 5, levers 8 and I and I2 are allmounted upon a horizontally arranged U-shaped sheet metal bracket IIwhich is constructed as shown in Fig. 8. The side walls IIiI of bracketII are provided with outwardly bent end portions l|--i| which aresecured to the front face of insulating base i by rivets lI-l8 shown inFig. 2. The side walls lI-II of bracket II are also drilled to receivehorizontally. arranged pivot pins 19 and 20, the former pivot pin beingarranged adjacent the under side of said bracket and at a point midwaybetween the ends thereof and the latter pivot pin being arrangedadjacent the upper side of said bracket at a point adjacent the rear endthereof. Contact carrier I and lever 8 of the snap operating mechanismare both pivotaliy mounted upon pivot pin l0 and lever 9 of the snapoperating mechanism is rotatably mounted upon pivot pin 2..

Contact carrier I is arranged between the side walls II of bracket II,andas shown in Fig. 9 the same comprises a molded insulating memberhaving vertically arranged spaced side arms 22-22 which are connected atopposite ends by bridging portions 2.! and 24 and intermediate theirends by a bridgin portion 25. The'upper ends of the side arms 22of'contact carrier I are recessed as shown at 28 to receive pivot 'pinis and the brid ng portion 24 of said contact carrier has a rivet 21molded therein which carries bridging contact I. Contact carrier 5 isheld in position upon pivot pin it and is also biased in a direction tomove bridging contact I into engagement with stationary contacts 2 and,I by the spring I which is connected at one end to the bridging portion25 of said contact carrier and at its opposite end to insulating base I,as shown at 2| in Figs. 3 and 4. The side arms 22 of contact carrier Iare each provided with an outill wardly extending stop projection 28 andcircuit opening movement of ,said contact carrier is limited byengagement of one of said projections with a stop surface 30 on theunder side of bracket I5.

Lever 8 of the snap operating mechanism comprises a U-shaped sheet metalmember having spaced side arms 3I-4i which are pivoted at their upperends upon pivot pin E9. The side arms iii of lever 8 straddle contactcarrier 5 and the side walls iii of bracket ll, andsaid side arms aremovable with respect to said contact carrier between the stopprojections 29 thereon and an adjustable screw stop 32 which is threadedinto an opening in insulating base I. Lever 9 of the snap operatingmechanism comprises a hook shaped sheet metal member arranged betweenthe side walls of bracket I5 and having one end pivoted upon pivot pin20. Lever 9 extends forwardly between the side walls 22 of contactcarrier Sand the free end thereof projects forwardly through a recess 34in the front wall of bracket I5. Lever 8 has a pointed rivet 35 fixed tothe lower end thereof which engages anindented cup washer 36 and lever 9has a pointed rivet 31 fixed thereto at a point below pivot pin I9 whichengages an indented cup washer 38. Spring II) of the snap operatingmechanism is held under compression between the cup washers 38 and 33.

With lever 9 in the position shown in Fig. 3 spring i0 is positioned sothat the force thereof acts on a line located to the rear of pivot pin I9. lever B is thus biased to move forwardly and the side arms 8! thereofengage stop projections 28 on contact carrier 5 to hold said contactcarrier in open position as shown in Fig. 3. During movement of lever 9from the position shown in Fig. 3 into the position shown in Fig. 4spring I0 assumes a position wherein the force thereof acts on a linelocated in, front of pivot pin l9. Lever 8 then snaps out of theposition shown in Fig. 3 into the position shown in Fig. 4 where-.

in the same engages stop 32 and contact carrier 5 is quickly moved intocircuit closing position under the action of spring 6. During returnmovement of lever 9 from the position shown in Fig. 4 into the positionshown in Fig. 3 spring I0 again assumes a position wherein the forcethereof acts on a line located to the rear of pivot pin i9. Lever 8 isthen snapped into the position shown in Fig. 3, and during finalmovement thereof into such position the same engages stop projections 29on contact carrier 5 to quickly move the latter into circuit openingposition against the action of spring 8.

Lever 9 is controlled by the fluid condition responsive device I and inthe embodiment il-- base into tapped openings in the end portions I! offrame I 5. The front end of bellows 40 has a pin 43 fixed thereto whichextends through an opening in base I and is provided with a pointed endwhich engages a cup member 44 fixed within an opening in lever 3. Cupmember 44 has a cone shaped recess in the rear face thereof forreceiving the pointed end of pin" and the front face of said cup memberis provided with a cone projection 45 which engages an indented washer48. Loading spring ii is held under compression between washer 46 and anut 4'l mounted upon screw I2. Nut

- compartment of the refrigerator. II contains an expansible fluid, asfor example 41 is held against rotation by a projection 48 on one sidethereof which engages within a slot 49 in one of the side walls I of'bracket Ii. Screw I2 is rotatably mounted within an opening in the frontwall of bracket II and is held against axial movement under the actionof spring II by a shoulder ll thereon which engages the rear face ofsaid front wall.

The above described control device may be used in connection withelectric refrigerators to effect starting and stopping of therefrigerator upon given temperatures within the food com- Dflrtmentthereof. For such service bellows 42 has a closed pipe extension 5|sealed to the rear end thereof to be arranged within the cooling Pipeextension methyl chloride, and upon temperature changes within thecooling compartment the pressure of the fluid within said pipe extensionvaries to effect operation of bellows 40.

Upon an increase in' temperature within the cooling compartment bellows40 expands and at a predetermined temperature determined by the opposingforce of spring II lever 9 is operated to move contact carrier 5 intocircuit closing position for starting of the refrigerator. Upon adecrease in temperature within the cooling compartment bellows 40contracts under the action-of spring II and at a predeterminedtemperature lever 9. is operated to move contact carrier I into openposition for stopping of the refrigerator. As 'is apparent, variation ofthe degree of compression of spring II varies the temperature values atwhich the refrigerator is started and stopped. Also adjustment of stop32 varies the position of lever 8 to vary the point at which said leveris operated during rearward movement of lever B. Adjustment of stop 32therefore varies the degree of temperature drop required to effectstopping of the refrigerator.

Knob I3 is formed of molded insulating mateposed between said shoulderand the rear end of said knob. The cam projection I4 is formed on theinner end of knob I3 and upon movement of said knob in a.counter-clockwise direction into a given extreme position said camprojection is adapted to engage the free end of lever 9 as shown in Fig.5 to move the same downwardly into the position shown in Fig. 3. Theknob I3 is thus operable at will to movelcontact carrier 5 into openposition for defrosting of the refrigera-tor. The front wall of frame I!is provided with a forwardly extending stop projection 56 whichcooperates with cam projection I4 to limit movement of knob l3 inopposite directions.

The rear face of insulating base 'I is provided with a circular recessII for receiving a conventiongi type of attachment plug and stationarycontacts 2 and 3 are provided with prongs I8 and II which extend throughopenings in said insulating base into said recess for engagement withthe contacts on the plug.

The device is also provided with: box-shaped enclosing casing 34 havinga face plate II associated with the front end thereof. Said casing andface. plate are formed of molded insulating material and, as shown inFig. 6, the same are held in assembled relation upon base I by screws $2which engage within tapped openings in the front wall of frame I. Theface plate ii may be of any desired shape to suit the apparatus uponwhich the device is to be mounted and in the embodiment illustrated saidplate is provided with tapped openings 63 for receiving a pair ofsecuring screws.

The control device may be used to control alternating current or directcurrent refrigerators. However, when the device is used to controldirect current refrigerators the same is provided with arc extinguishingmeans comprising a permanent magnet 64, which is held in position uponthe front face of insulating base I by a shoulder 65 on the interior ofcasing 80. Magnet GI is U- shaped and the pole faces thereof are locatedbelow contacts 2 and 3 and are held in spaced relation with'respect tosaid contacts by shoulders 66 formed on the face of insulating base I.

What I claim as-new and desire to secure by Letters Patent is:

1. In a circuit controlling device, in combination, a contact elementmovable about a fixed axis and biased toward closed position, a levermovable about said axis between given extreme positions and arranged tomove said contact element into open position during final movement intoone of said positions and to permit closure thereof during initial-movement out of said position, an overcenter spring for moving saidlever in opposite directions between said extreme positions with a snap,a pivoted operating member for operating said contact element throughthe medium of said spring, and a fluid condition responsive operatingdevice associated with said operating member.

2. In a circuit controlling device, in combination, a contact elementmovable about a fixed axis and biased toward closed position, a levermovable about said axis between given extreme positions and arranged tomove said contact element into open position during final movement intoone of said positions and to permit closure thereof during initialmovement out of said position, an overcenter spring for moving saidlever in opposite directions between said extreme positions with a snap,a pivoted operating member for operating said contact element throughthe medium of said spring, a temperature responsive operating deviceassociated with said operating member, said device having a loadingspring associated therewith, a screw element manually operable to adjustsaid loading spring to vary the temperature values at which said contactelement is moved into open and closed positions, and means associatedwith said screw element for engaging said operating member to effectmovement of said contact element into open position at will.

3. In a circuit controlling device, in combination, a control switch, asnap operating mechanism therefor including an operating member movablein opposite directions into given extreme positions to open andclosesaid switch, fluid condition responsive means acting directly uponsaid member to open and close said switch under predeterminedconditions, said means including a loading spring and a manual controlelement having an associated screw for adjusting said loading spring andan associated cam for engaging said operating member to move the sameinto one extreme position for opening of said control switch.

4. ma circuit controlling device, in combination, a control switch, asnap operating mechanism therefor including an operating member tion, arear insulating base, a bracket fixed to the front face of said base, amovable contact element pivotally mounted upon said bracket and biasedtoward closed position, a lever pivotally mounted upon said bracket,said lever being movable between given extreme positions and beingarranged to move said contact element into open position during finalmovement into one of said positions and to permit closure thereof duringinitial movement out of said extreme position,

an over center spring for moving said lever in opposite directionsbetween said extreme positions with a snap, a second lever pivotallymounted upon said bracket and movable between given extreme positions tooperate said former lever through the medium of said spring and a fluidcondition responsive operating device for said second lever mounted uponsaid base.

6. In a circuit controlling device, in combination, a rear insulatingbase, a bracket fixed to the front face of said base, a movable contactelement pivotally mounted upon said lpacket and biased toward closedposition, a lever pivotally mounted upon said bracket, said lever beingmovable between given extreme positions and being arranged to move saidcontact element into open position during final movement into one ofsaid positions and to permit closure thereof during initial movement outof said position, an over center spring for moving said lever inopposite directions between said extremepositions with a snap, a pivotedoperating member carried by said bracket for operating said leverthrough the medium of said spring, a pressure responsive device foroperating said member, said device being mounted upon said base andhaving a loading spring associated therewith and a screw elementrotatably mounted upon said bracket for adjusting said loading spring tovary the pressure values at which said switch is opened and closed.

I '7. In a circuit controlling device, in combination, a rear insulatingbase, a bracket fixed to the front face of said base, a movable contactelement pivotally mounted upon said bracket and biased toward closedposition, a lever pivotally mounted upon said bracket, said lever beingmovable between given extreme positions and being arranged to move saidcontact element into open position during final movement into one ofsaid positions and to permit closure thereof during initial movement outof said position, an over center spring for moving said lever inopposite directions between said extreme positions with a snap, apivoted operating member carried by said bracket for operating saidcontact element through the medium of said spring, a pressure responsivedevice for operating said last mentionedlever, said device being mountedupon said base and having a loading spring associated therewith, a screwelement rotatably mounted upon said bracket for adjusting said loadingspring to vary the pressurevalues at which said switch is opened andclosed, and a cam associated with said screw. tor engaging saidoperating member to move the same into a position to eflect opening ofsaid switch. L 8. In a refrigerator control device, in combi- 5 nation,an insulating base, a snap switch mecha: nism mounted upon said base andincluding a movable bridging contact and a pair of cooperatingstationary contacts fixed to said base, a magnetic blowout deviceassociated with said 10 contacts comprising a permanent magnet havingpole faces located adjacent said stationary contacts, said insulatingsupport being recessed to receive said magnet and an insulatingbox-shaped enclosing casing for said switch mechanism 15 mounted uponsaid base, said magnet being held in place upon said base by saidcasing.

9. In a circuit controlling device, in combination, a contact elementmovable about a fixed ems and biased toward closed position, a lever 20movable about a fixed axis between given extreme positions and arrangedto move said contact element into open position during final movementinto one 01' said extreme positions and to permit closure thereoi'during initial movement out of said position, an over center spring 5for moving said lever in opposite directions between said extremepositions with a snap, a pivoted operating member for moving saidcontact element through the medium of said spring, a fluid conditionresponsive device associated with 10 said operating member and having aloading spring associated therewith and a single manual controlelementoperable to adjust said loading spring for variation of. theconditions under which said switch is opened and closed and alsooperable 15 at will to move said operating member into a position toeflect opening of said contact element through the medium of said overcenter spring.

CLARENCE W. KUHN. 20

